hi all , I do not like to update my gentoo frequently cause compile takes me a long time,but some days ago, I decided to upgrade my Xorg server to 1.13 and gentoo-source kernel 3.6.2 . it sucks me . the X was crash at login window, the screen was blank. sometimes you can see the mouse loading with the circle.I try to fix this as follows ,but it didn't work. (my video card is Nvidia Geforce 8400M) my Xorg.conf use nvidia-xconfig auto to generate.

1.update Nvidia driver to latest (304.43?) in the portage (ACCEPT_KEYWORDS="~amd64")
2.download latest Nvidia driver form Nvidia Official website and install it
3 dowgrade Nvidia driver in the portage
my Xorg.log file is here http://pastebin.com/FZy7TRsf
the ERROR is